1. Field of the Invention
The present invention relates to a height-adjustable leg suitable to support the work or the support surface of a table. The present invention further relates to a table having at least one height-adjustable leg.
2. Description of the Related Art
In the furnishing and in particular the table manufacturing industry, the technique of using support legs for a table which are adjustable in height so as to position and block the support surface at a desired height from the floor is well known.
In particular, telescopic legs exist extending along an axis of elongation generally substantially vertical, in particular formed of several reciprocally sliding segments or members which fit inside each other.
Such known telescopic legs require the use of precise sliding guides and carriages, which for aesthetic reasons must be hidden inside the members, which further complicates the structural complexity.
Such guide rails and carriages for the known legs are designed to minimize the sliding friction between the leg members. To do this a minimum clearance is often generated between the mechanical components which form the coupling between the various leg members, to facilitate sliding. Such minimal clearance produces the disadvantage of allowing a minimum relative displacement between the leg members outside the axis of elongation, producing a feeling of instability and poor quality construction, as well as potentially causing vibrations.
Among other things, when the known telescopic leg is formed of more than two members, and therefore at least one intermediate member is present between them, the problem of moving such member in synchrony with the relative movement between the end members arises. This often requires complicated mechanisms for transmitting the movement of such intermediate members according to the movement of the upper end with respect to the base end. These mechanisms are often quite complex and require belt drives, pulleys, etc. Furthermore the need to conceal these mechanisms inside the leg greatly complicates the manufacturing complexity and number of components required.
Moreover, these known adjustable legs, since designed to reduce or possibly eliminate the sliding friction between the leg members, do not provide in themselves, any structural support capacity in the direction of elongation or extension of the leg.
Thus the structural support action of such known legs is exclusively entrusted to additional structural members, sometimes formed of a linear actuator, such as a screw-and-nut system positioned parallel to the elongation axis of the leg, which connects at least the base member and the upper member of the adjustable leg to each other.
According to the prior art, therefore, all the weight of the table top and of the objects placed on it, but also the weight of the leg members, weigh exclusively on the linear actuator.
Since all the weight rests exclusively on the actuator, it must be oversized to ensure sufficient structural stability of the table when the support surface is stopped at a predetermined height, and also to ensure safe use to prevent unintentional lowering of the table top.
The greatly reduced spaces inside the leg for housing the actuator do not permit the use of sufficiently sturdy linear actuators to overcome this problem.
These limits of reduced structural stability and possible minimum displacements between the segments forming the known telescopic leg which conceals within it actuators and guide systems of said segments, makes it impossible to use a single known telescopic leg to support the support surface of a table, since such support surface would not be rigidly supported by the singe support leg, and would give the user an unpleasant sensation of poor quality construction and reduced safety of use.
The above limits of reduced structural stability and possible minimum displacements between the segments forming the known telescopic leg make the application of a single, known telescopic leg to support the support surface of a table, supporting it in a decentralized position, i.e. supporting a cantilever table top, even more unthinkable.
Such latter requirement to support the table top by means of a single leg in the vicinity of an edge of the table, not satisfied by the prior art, is particularly felt for both aesthetic and functional reasons, in fact, such a solution would provide both a linear and minimalist aesthetic effect, and convenience of use, leaving all the space below the table top free for the user's legs.